A faster but unpleasant method of stopping an addictive habit, such as drugs or alcohol. It means that you just totally, completely stop, and never do it again (or at least try to).

Going cold turkey is opposed to stopping it by gradually doing it less and less, or stopping it with help like special gum or medicine. You don't get any help; you just stop.

Lydia tried to smoke only one cigarette a week, but she ended up going back to her old habits. She decided to try out going cold turkey.

"Cold turkey" is a term describing the actions of a person who gives up his habit or addiction at a single moment, rather than through gradually easing the process through tapering off or supplemental medication. The term allegedly derives from the comparison of a cold turkey carcass and the state of a withdrawing addict -- most notably, the cold sweats and gooseflesh. It is often preceded by the word 'going', as 'going cold turkey'."--Wikipedia

Without preparation. First used in correlation with withdrawl from an addictive substance in the 1920s with regards to heroin addiction. The idea being that "cold turkey" is a food that requires little to no preparation to eat - hence doing something "cold turkey" means the action will be done without preparation & immediately. Also connected to the notion that the symptoms of withdrawl from many substances include cold sweats (moisture), and sallow skin - much like that of a cold, dead, turkey.

The ultimate Minute to Win It challenge. The contestant has 60 seconds to ejaculate starting completely flaccid (cold turkey) and using no pornographic material whatsoever.

British Lady: Your million dollar challenge is...Cold Turkey
*Audience groans*
Contestant: In front of all them? On national television?
Guy Fiere: Let's hope you can finish strong!
British Lady: Your time begins...now.

When somebody quits something without weaning themselves off of it.
Could be anything E.G: smoking, jacking off, television.
Originates from when a smack (or any opiate for that matter, medical or not) addict stops taking drugs completely. The effects are feeling "cold" (from the inside) no matter what temperature it is or how many blankets you are using.
The turkey part comes from the same origin and when your skin goes goosepimply...like a turkey.
I speak from personal experience.

Johnny went cold turkey last week. He's been wrapped up in bed ever since, but still feels freezing cold.

Cold turkey refers to the clammy, cold, sweaty and goose bumped state of the heroin addict that is trying to "kick" the habit. This happens when the junkie decides to give up heroin without any sort of support mechanism - such as methadone - to take the place of the heroin. The body reacts by turning cold, clammy, sweaty, and the skin resembles that of a cold turkey.